swagger-parser-v2-converter removes enum constraint from numeric types

It is valid, in both OpenAPI v2 and v3, to constrain a schema of numeric type (type: integer or type: number) with enum.

The swagger-parser-v2-converter, when converting a file from v2 to v3, removes such enum constraints.

How to reproduce:

1. Store this file as v2.json.

v2.json.gz

2. Store this file as ConvertOpenAPIV2ToV3.java.

ConvertOpenAPIV2ToV3.java.gz

Compile it with a classpath that contains
slf4j-api-1.5.8.jar
slf4j-jdk14-1.5.8.jar
jackson-core-2.9.9.jar
jackson-dataformat-yaml-2.9.9.jar
jackson-databind-2.9.9.jar
jackson-annotations-2.9.9.jar
commons-io-1.4.jar
commons-lang3-3.1.jar
swagger-models-2.0.8.jar
swagger-parser-v3-2.0.12.jar
swagger-core-2.0.8.jar
swagger-parser-core-2.0.12.jar
swagger-parser-v2-converter-2.0.12.jar
swagger-parser-1.0.44.jar
swagger-core-1.5.22.jar
swagger-models-1.5.22.jar
snakeyaml.jar

3. Run it with two arguments, namely the absolute file name from step 1 and the absolute file name of the destination file.

4. The output I got is:

v3.json.gz

As you can see, it has omitted the enum property of integerVar and decimalVar.

Start with the swagger-parser-v2-converter using the supplied v2.json and ConvertOpenAPIV2ToV3.java reproducer, then compare the generated v3.json with the source schema. Verify that enum constraints on integerVar and decimalVar are preserved after conversion; the issue does not name a repository source file or test.